1964

5.3

1975

5.3

1981

5.6

1997

5.2

1982

6.8

1977

6.7

1969

6.1

1996

7.7

1996

6.0

1969

6.0

1988

0.0

1998

6.0

1980

5.7

1977

5.9

1972

6.8

1994

6.1